I think it's kind of hard to quantify complexity in a way that compares nicely across domains. For example, a lot of the complexity in a browser comes from need

I think it's kind of hard to quantify complexity in a way that compares nicely across domains. For example, a lot of the complexity in a browser comes from needing to service ~billions of users across thousands of devices using loosely implemented standards. This is quite a different problem to building an aircraft carrier, where you're going to run in to hard engineering and physics problems but you only have to target ~10k well trained users.